jan-feb-2021

Pruning of almond trees often takes place during the winter months when trees are dormant, which also coincides with the rainy season in California and thus the time when spores of fungal pathogens are most prevalent. As pruning wounds are highly susceptible to infection and early infection of young trees could challenge the good establishment of almond orchards, protection of pruning wounds with a fungicidal product or a biological control agent is recommended to reduce infection by canker pathogens. Wound Protection Can Reduce Risk of Infection Once a tree is infected with canker diseases, it generally cannot be cured, thus; prevention is key. Wound protection is recommended particularly following major pruning events such as primary and secondary scaffold selection and maintenance pruning if performed during the fall, winter or spring in California. Three years of field experiments spent investigating pruning wound protection using various fungicidal products – Topsin M (Thiophanate-methyl, FRAC 1 ) and the Trichoderma biocontrol product Vintec ( Trichoderma atroviride SC1 ) – demonstrated excellent disease control of 80 to 1 00 percent when those products were applied to fresh wounds immediately after pruning. Fungicides such as Quash (Metconazole, FRAC 3), Quilt Xcel This graph demonstrates the efficacy of various fungicides in protecting pruning wounds against main fungal canker pathogens, as illustrated by Mean Percent Disease Control (MPDC). Photo courtesy of Florent P. Trouillas. 4 1 J A N U A R Y – F E B R U A R Y 2 0 2 1